If you have no attic you have not been able to get a rooftop mounted whole house fan until now.  You get a 20 inch diameter fan and throat that uses industry standard roof flashing. This kit comes with a FAMCO gravity damper built into the shell and with a wall cabinet to hide the industrial look. For  more information see Thorwaldson Rooftop Whole House Fans. 


An important design feature is that the Tornado turbine has two high performance bearings at the top of the shaft – two sealed stainless steel ball bearings 3-1/2 inches apart. 

SS bearing

Below is an artist’s conception of the new ER-8000. It uses the new Tornado rooftop ventilator – a rotating turbine with vertical blades that offer the best air flow possible. 

This drawing shows the recommended installation in a roof. What is not shown is a flashing that might be added to improve the water proofing of the opening. Also, the drawing shows that most of the unit is above the roof so it is likely that an installer will want to brace the assembly with straps running at a 45 degree angle from just below the turbine down to at least 3 places on the roof. The bottom section is a 20 inch diameter shell with damper doors inside. It will need at least 3 brackets around its perimeter to keep it above the roofline.

Wiring is made easy because the AC power wires and the speed control wires are inside the shell and come out the bottom. You can see a small box just to the left of the bottom frame. That is expected to be a junction box for connecting the wires. 

Here is a picture of a rooftop in final test. This new Tornado top has 8,000  CFM flowing through it and it is turning at just 300 RPM. 


This Tornado rainproof top is the most effective rain hat in history because it allows perfect air flow at all motor speeds and perfect rain deflection. Note that if there is no wind rain falls straight down and off the top. If there is any wind the turbine blades deflect rain drops. 

ModelCFMDia PriceVariable?
ER-8000800020 2224.40YES.

Installation is the same as putting a simple pipe through your roof. In this case the pipe is our 20 inch diameter shell with motor and blade inside. The rain hat is mounted on top of the motor and blade shell. This work should be done by a licensed roofing contractor and you can find one locally in almost every city in the world. That shell can be on top of your roof or below it. The assembly includes a damper below the motor so air cannot fall down when the motor is off.

This fan is very quiet. It was measured at just 61 Db  when 15 feet away.